Deutsche Bank has received a subpoena from the U.S. special counsel investigating possible collusion between President Donald Trump's campaign and Russian Federation.

In an interview with the New York Times in July, Trump, asked if Mueller's investigation would cross a "red line" if it expanded to look at his family's finances beyond any relationship to Russia, Mr. Trump said, "I would say yes". It's unknown if the subpoena is related to Mueller's investigation into Russian meddling in the 2016 election, or rather part of a separate investigation.

President Donald Trump's personal lawyer John Dowd disputed that account, saying he had been told by Deutsche Bank that no such subpoena had been issued.

Trump has more debt with Deutsche Bank than any other lender.

Special counsel Robert Mueller has issued a subpoena to Germany's largest bank, in a possible sign the investigation into Russian election interference may be expanding toward President Trump's finances.

Germany's largest bank received a subpoena from Special Counsel Robert Mueller several weeks ago to provide information on certain money and credit transactions, the person said, without giving details, adding that key documents had been handed over in the meantime.

"We have confirmed that the news reports that the special counsel had subpoenaed financial records relating to the president are false", Sekulow said.

Mr Trump and Deutsche Bank have not always been on good terms. Deutsche Bank may be glad it's being forced to hand over information.

It's clear, Harding tells Rolling Stone, that Deutsche Bank Moscow "was compromised" and did this "unseemly, Faust-like deal with VTB to make very big profits, very quickly and to stun its rivals in Moscow, other investment banks, just by having the right people with the right FSB connections".

As Mueller's investigation unfolds, Trump has gone on the offensive.

The $300 million includes a $170 million loan Trump took out to complete a hotel in Washington, two mortgages against his Trump National Doral Miami resort, and a loan against his tower in Chicago.

Trump told the New York Times this past summer he would consider it a "violation" if Mueller were to expand the probe beyond Russian Federation.

Asked if delving into his and his family's finances unrelated to the Russian Federation probe would cross a red line, Trump replied, "I would say yeah".

Deutsche Bank is not the only Trump-related business interest that is attracting the attention of investigators. A second source familiar with the investigation said that the subpoena was linked to Mr Trump's indicted former campaign chairman Paul Manafort.

Deutsche Bank countersued and the two sides eventually settled.

Mueller has also obtained a guilty plea from Trump campaign foreign policy advisor George Papadopoulos.